NFC is a 13.56 MHz carrier based secure communication technology which has found its uses in as personal ID, money transaction etc. An NFC system includes an NFC tag that contains information and an NFC reader that reads information from the NFC tag. An NFC tag can be a passive NFC tag or an active NFC tag. The passive NFC tag utilizes the magnetic field or radio frequency (RF) field generated by an NFC reader for operation. When the magnetic field of the NFC reader is incident on the antenna of the passive NFC tag, a controller inside the passive NFC tag accesses its internal memory and provides information to the NFC reader by modulating the incident magnetic field. An active NFC tag generates its own magnetic field to interact with an NFC reader. It is to be noted that NFC communication technology works on the same principle as RF communication technology. Hence, the NFC devices (readers/tags) can interchangeably interact with RF devices (readers/tags).
An NFC device can communicate to a range of 50 mm, and the incident magnetic field or RF field on NFC device antenna can vary from 0.15 A/m to 12 A/m. Various applications require an NFC device antenna to have a high dynamic range. At higher field extremes, very high voltage swing is present on the NFC device antenna that could reach excess of 40 volt which would damage the NFC device.